Computing devices have an operating system. The operating system is a software program that enables the execution of software applications on the computing devices hardware. The operating system is loaded on a processor located in the computing device. Many applications have found there way onto mobile devices. Some of these applications involve audio processing and/or video processing.
The term audio processing may refer to the processing of audio signals. Similarly, the term video processing may refer to the processing of video signals. Audio signals are electrical signals that represent audio, i.e., sounds that are within the range of human hearing. Similarly, video signals are electrical signals that represent video. Audio or video signals may be either digital or analog. Many different types of computing devices may utilize audio and video processing techniques. Examples of such computing devices include desktop computers, laptop computers, workstations, wireless communication devices, wireless mobile devices, personal digital assistants (PDAs), smart phones, iPods, MP3 players, handheld gaming units or other media players, and a wide variety of other consumer devices. As used herein any of these examples of computing devices are considered “media devices”.
Audio compression is a form of data compression that is designed to reduce the size of audio files. There are many different audio compression algorithms that are in use today. Some examples of audio compression algorithms include MPEG-1 Audio Layer 3 (MP3), Advanced Audio Coding (AAC), High Efficiency AAC (HE-AAC), HE-AAC version 2 (HE-AAC v2), Windows Media Audio (WMA), WMA Pro, etc.
Similarly video compression (which sometimes may be used to compress pictures as well as video) is a form of data compression that is designed to reduce the size of video (or picture) files. There are many different video compression algorithms that are also in use today. Some examples of video compression algorithms include JPEG Base Profile, JPEG2000, MPEG-1, MPG-2, MPEG-4 Simple Profile, MPEG-4 Advanced Simple Profile, H.263 Base Profile, H.264 Base Profile, H.264 Main Profile, Windows Media Video 9 series, including the VC1 standard, etc.
The audio file or video file may have different formats depending on the audio or video compression algorithms used to compress the audio or video signals. The compressed data may sometimes be referred to as a bitstream. The bitstream (i.e., the compressed audio file or compressed video file) may be stored in a memory. Sometimes the bitstream is encrypted or stored in a format associated with an operating system of the computer or mobile device. To decompress the bitstream (since it may represent compressed data) and to decrypt the bitstream (if it is encrypted) requires many computations per second.
The processor (sometimes called an application processor) which runs the application software interacts with a specialized processor. One type of specialized processor is known as a digital signal processor (DSP). The application processor where the operating system is loaded retrieves the bitstream from memory and passes it to the DSP to decrypt and/or decompress. Processing a bitstream in this manner often consumes a lot of power. Finding a technique to process the bitstream at a lower power is desired.